End File

NTFSD
1

hi,all:
In File Filter driver,in IRP_MJ_WRITE operation how can I know end of a file?
By currentIrpStack->Parameters.Write.ByteOffset can I know ?
In close and clearup i can do this,but I dont want use this?

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2

Filter noncached IO only, in this case, you have 100% guarantee that the write is within the end-of-file.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: xinling zhang
To: Windows File Systems Devs Interest List
Sent: Saturday, January 08, 2005 12:44 PM
Subject: [ntfsd] End File

hi,all:
In File Filter driver,in IRP_MJ_WRITE operation how can I know end of a file?
By currentIrpStack->Parameters.Write.ByteOffset can I know ?
In close and clearup i can do this,but I dont want use this?

Do You Yahoo!?
ע???һ??Ʒ?ʵ??Ż???ѵ??? — Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17 You are currently subscribed to ntfsd as: xxxxx@storagecraft.com To unsubscribe send a blank email to xxxxx@lists.osr.com

3

sorry i dont know what you said i mean is when write a file how can i know end of a file wirte operation in filemon can you explain your mean ?

“Maxim S. Shatskih” wrote: Filter noncached IO only, in this case, you have 100% guarantee that the write is within the end-of-file.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: xinling zhang
To: Windows File Systems Devs Interest List
Sent: Saturday, January 08, 2005 12:44 PM
Subject: [ntfsd] End File

hi,all:
In File Filter driver,in IRP_MJ_WRITE operation how can I know end of a file?
By currentIrpStack->Parameters.Write.ByteOffset can I know ?
In close and clearup i can do this,but I dont want use this?

---------------------------------
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4

Use the FCB, there ate all three file sizes (FileSize,
AllocationSize and ValidDataLength).

Filter noncached IO only, in this case, you have 100%
guarantee that the write is within the end-of-file.

A paging I/O write request can go past end of file
(I speak about request, not about result)
So you are not sure, whether the write range in the IRP is
before end of file, but you may be sure that the file system
will reject any requests that go after the end of the file.

L.

5

thanks very much!
i will try later and i have a question.
i back up a *.doc in File filter real time,but there are some questions.
for exampe,source file is C:\file.doc and destination file is D:\file.doc
i open C:\file.doc and produce a ~$file.doc ,at the same time i create
a same file in D:~$file.doc
when i save my source file ,the os produce some operations i do same operatiron in D:,but i dont backup successfully ,i backup successfully its context ,but when rename i fail some time for share deny the first time is successfuly
Maby i dont explian these all Can you undersdand i ?
thanks

Ladislav Zezula wrote:
Use the FCB, there ate all three file sizes (FileSize,
AllocationSize and ValidDataLength).

> Filter noncached IO only, in this case, you have 100%
> guarantee that the write is within the end-of-file.

A paging I/O write request can go past end of file
(I speak about request, not about result)
So you are not sure, whether the write range in the IRP is
before end of file, but you may be sure that the file system
will reject any requests that go after the end of the file.

L.

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Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17

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